Electrical contact element and method for manufacturing same

Abstract

An electrical contact element and a method of manufacturing an electrical contact element having a connecting segment which is formed of a copper sheet and comprising a coating overlaying the copper sheet having at least two layers. A first layer contains at least 60% by weight of tin. A second layer is disposed between the first layer and the copper sheet. The second layer contains a copper-containing alloy. The copper-containing alloy contains 40 to 80% by weight of copper and 20 to 60% by weight of zinc. The combined percentage by weight of copper and zinc in the second layer is at least 90%. A third layer containing tin may be disposed between the second layer and the copper sheet. A fourth layer containing zinc may be disposed on a side of the first layer opposite the second layer.

I claim: 
     
       1. An electrical contact element having a connecting segment which is formed of a copper sheet and comprises a coating, wherein the coating comprises:
 a first layer containing at least 60% by weight of tin; and 
 a second layer disposed between the first layer and the copper sheet and containing a copper-containing alloy, wherein the copper-containing alloy contains 40 to 80% by weight of copper and 20 to 60% by weight of zinc, wherein the combined percentage by weight of copper and zinc is at least 90%. 
 
     
     
       2. The electrical contact element according to  claim 1 , wherein the second layer has a thickness of 0.5 to 5 μm. 
     
     
       3. The electrical contact element according to  claim 1 , wherein the second layer consists of the copper-containing alloy. 
     
     
       4. The electrical contact element according to  claim 1 , wherein the first layer has a thickness in a range of 1 to 15 μm. 
     
     
       5. The electrical contact element according to  claim 1 , wherein the first layer contains up to 40% by weight of zinc. 
     
     
       6. The electrical contact element according to  claim 1 , wherein the coating comprises a third layer disposed between the second layer and the copper sheet, wherein the third layer contains tin. 
     
     
       7. The electrical contact element according to  claim 6 , wherein the coating comprises a fourth layer disposed on a side of the first layer opposite the second layer wherein the fourth layer contains zinc. 
     
     
       8. A method for manufacturing an electrical contact element, comprising the steps of:
 providing a base body; 
 applying a second layer on the base body, wherein the second layer contains a copper-containing alloy, wherein the copper-containing alloy contains 40 to 80% by weight of copper and 20 to 60% by weight of zinc, and wherein the combined percentage by weight of copper and zinc is at least 90%; and 
 applying a first layer, containing at least 60% by weight of tin, on a side of the second layer opposite the base body. 
 
     
     
       9. The method according to  claim 8 , further comprising a step of heat treating the electrical contact element, wherein the heat treating step is performed after the step of applying the first layer. 
     
     
       10. The method according to  claim 8 , wherein the layers are each applied by a process selected from the group consisting of galvanic technique, vapor coating, sputtering, dip coating, spray coating, and any combinations of the above processes. 
     
     
       11. The method according to  claim 8 , wherein the base body is formed of a fire-tinned copper sheet. 
     
     
       12. The method according to  claim 9 , wherein the heat treating step is performed in a temperature range of 50 to 350° C. for a time period of 1 second to 48 hours. 
     
     
       13. The method according to  claim 12 , wherein the heat treating step is performed in a temperature range of 220 to 270° C. for a time period of 5 seconds to 2 minutes.